Anatoly Stoyanovsky, director of RIA Novosti's software development, said the website was hit by a denial-of-service attack last week.
"Our on-duty services immediately responded to the emergency. Automatic filtering mechanisms were activated as planned," he was quoted Friday as saying. "We saw the peak number of requests per minute reaching some 150,000, but within several minutes, malicious traffic was blocked."
He did not indicate blame in the attack. Denial-of-service attacks overwhelm a website with data requests, forcing some computer systems to crash.
Frustration with the government of President Vladimir Putin has been high since his election to a third non-consecutive term last year. Stoyanovsky didn't indicate whether the attack was foreign or domestic.
The Russian government said Monday it lifted a ban on the political activities of the opposition Left Front movement. Its leader, Sergei Udaltsov, is under house arrest for allegedly plotting against the state.
Intelligence agencies across the world have said cyber issues are an emerging threat to national security.